Rotavirus infection symptoms
Rotavirus infection is an acute intestinal disease caused by rotaviruses characterized by gastrointestinal lesions as gastroenteritis. This infection has increased significantly in recent years among acute intestinal infections of the viral nature. The use of modern methods allows to prove the role of viral agents in the development of acute intestinal infections( acute intestinal infections) in 50-60% of children.
The structure of viral diarrhea is dominated by rotavirus gastroenteritis , which is registered in 35-40% of patients, and among children under the age of three their frequency exceeds 60%.Noroviruses cause OCD in 18-20% of children, adenoviruses in 10%.The prevalence of other viruses( astroviruses, saloviruses, caliciviruses) is much lower - from 0.3 to 3%.
Virus agents of OCD dominate in all seasons of the year. But rotaviruses are leading in frequency detected in winter and spring months. In autumn, noroviruses are most often identified, which account for up to 1/4 of all cases of OCI registered at this time of year. The incidence of adeno- and astroviral infections is subject to less significant fluctuations throughout the year.
Etiology .Rotaviruses are one of the etiological agents of diarrhea in children and young animals, including calves, piglets, mice, rabbits, deer, lambs, and monkeys.
The name "rotavirus"( rota - wheel) is based on an electron microscopic image of the outer edge of the capsid in the form of a rim of the wheel surrounding the radial spokes emerging from the inner core. The size of the virus particles is 65-75 nm. Contains RNA, hemagglutinin and glycoprotein.
Rotavirus is relatively stable. Resistant to the effects of physical and chemical factors.
In feces at room temperature, infectious properties persist up to 7 months, which are lost when heated to a temperature of 50 ° C and above, when frozen, treated with surfactants. Infectiousness increases when treated with proteolytic enzymes( pancreatin, trypsin).
The presence of cross species infection has been experimentally established, but in natural conditions there is no data on such infection. The infection of animals with human rotavirus causes the development of diarrheal diseases in newborn animals( piglets, monkeys).
Rotavirus penetrates and infects enterocytes in villi in the small intestine. It multiplies in the cytoplasm, damaging the suction cells, ultimately leading to a disruption in the digestive function of the intestine. The lysis of infected cells facilitates the release of the virus into the lumen of the intestine, which leads to the accumulation of a large number of feces in the feces.
Diarrhea is associated with a pathology of absorption, including impaired absorption of glucose and sodium. Highly differentiated suction cells of the villi are replaced by immature crypt cells, unable to immediately compensate for the violation of the absorption process.
The source and reservoir of infection is only a person( patient or carrier).The patient excretes the pathogen in the external environment for 2-3 weeks. For children, the source of infection is mainly adults. The carrier is registered both in children, including in newborns, and in adults.
The causative agent is transmitted by a contact-household way, nosocomial, food and water outbreaks are possible.
The susceptibility to rotavirus is universal, the disease can occur at any age, but the highest incidence is recorded in children 6-12 months. In children of the first six months of life rotavirus infection is rare.
In children of early age, rotavirus gastroenteritis often occurs as a mixed infection( in combination with salmonellosis, shigellosis, opportunistic intestinal infection).
Rotavirus gastroenteritis is characterized by an increased incidence in winter and spring, which is explained by better preservation of the virus at low temperatures.
After the transferred disease is formed unstable immunity, in connection with which there are possible repeated cases of the disease.
Pathogenesis. Although a symptom complex characterized by acute gastroenteritis occurs with rotavirus infection, it is believed that viruses penetrate only the epithelium of the small intestine, mainly into the epithelial cells of the duodenum and the upper parts of the jejunum.
Penetration of the virus into epithelial cells causes accelerated progression of epithelial cells from the base of the villi to their apex. The cells do not have time to differentiate, their life time is shortened, the content of enzymes in them decreases, disaggregation is disrupted, their accumulation in the lumen of the intestine occurs, which attracts water and prevents its absorption, and osmotic diarrhea develops.
Completion of the infectious process is due to the disappearance of virus-sensitive cells of villous epithelium and their replacement by virus-insensitive immature epithelial cells. The role of interferon in blocking the infection is possible.
The pathoanatomical picture. When microscopic examination of the mucosa of the small intestine, areas with a smoothed surface, truncated villi are identified, infiltration of the mucous membrane with mononuclear cells is noted. After 4-8 weeks, the mucosa of the small intestine is completely normalized.
Classification of rotavirus infection:
I. Form:
1. Typical:
• gastroenteritis;
• gastritis;
• enteritis.
2. Atypical:
• erased;
• subclinical.
II.By gravity:
1. Light.
2. Medium-heavy.
3. Heavy.
III.Downstream:
1. Acute.
2. The protracted.
3. With complications.
4. Mixt infection.
The incubation period lasts from 10 hours to 3 days. The disease begins acutely. Early signs of the disease include diarrheal syndrome. The stool with rotavirus infection is abundant, watery, yellow, foamy, with a sharp odor.
In mild form of the disease, stools can remain mushy, and the frequency does not exceed 5 times a day.
With a moderate form of the disease, stool frequency can reach 10 times a day.
Vomiting occurs simultaneously with diarrhea, but more often for several hours ahead of her. Often at the beginning of the disease, nausea is noted.
In mild form of the disease, vomiting is single or absent.
With moderate form of rotavirus infection, vomiting is repeated( 3-4 times), but in most patients it ends within 24 hours.
With a mild form of the disease, body temperature usually remains normal, intoxication is absent or mild.
Moderately severe forms of infection are accompanied by a short( 1-3 days) increase in body temperature, moderately expressed symptoms of intoxication. Possible the development of excoxicosis.
Rotavirus infection is characterized by abdominal pain, bloating, rumbling along the bowels. With a mild course of the disease, this symptomatology is poorly expressed, with a moderate - more distinct.
In 20-60% of patients, symptoms of catarrh of the upper respiratory tract are recorded. In this case, hyperemia and granularity of the mucous membrane of the soft palate, palatine arches, and posterior pharyngeal wall are found. Patients complain of coughing, perspiration in the throat, difficulty in nasal breathing. In some cases, catarrhal symptoms precede gastrointestinal manifestations, most appear somewhat later. The degree of severity of catarrhal phenomena depends on the severity of the rotavirus infection.
Features of the course of rotavirus gastroenteritis of newborns and children of the first year of life. Rotavirus infection in infants develops rarely. It is possible to develop both sporadic cases and group outbreaks in maternity hospitals. Infection occurs from mothers or staff.
In children of the first 6 months of life, the disease is also rare. The highest incidence is registered in children aged 6-12 months.
The disease often occurs severely due to the development of dehydration and complications. Especially it is characteristic for children of early age from "risk groups"( perinatal nervous system damage, artificial feeding, exudative diathesis, VUI, etc.).
In 90% of newborns with rotavirus infection secondary lactase deficiency is formed. This is manifested in an increase in the duration and intensity of diarrhea, the appearance of pain and anxiety that increase after eating, a deeper violation of the water-salt balance. In some patients lactase deficiency disappears during convalescence, but 50% of them are discharged with this pathology, which requires appropriate corrective therapy, sometimes - repeated hospitalization.
In children of early age, rotavirus gastroenteritis often occurs as a mixed infection( in combination with salmonellosis, shigellosis, opportunistic intestinal infection).
Due to the formation of mixed infection, the clinical manifestations of the disease change. In particular, the stool acquires entericolitic or even hemocolytic character. The fever is more pronounced( 38-39 ° C) and persists for a long time( 5-7 days).Develop toxicosis and exsicosis. Recovery comes in 2-3 weeks. The possibility of a lethal outcome is not excluded.
Diagnosis of rotavirus infection is carried out on the basis of epidemiological data, taking into account the leading syndrome "secretory diarrhea", as well as the results of laboratory tests - virologic and serological.
Reference diagnostic criteria for rotavirus gastroenteritis:
• frequent registration in the winter season;
• sharp start;
• repeated vomiting( within 1-2 days), often preceding the onset of diarrhea;
• the stool is liquid, watery, plentiful, without pathological impurities, often foamy;
• abdominal pain, often intense, with predominant localization in the epigastric and peripump areas;
• rumbling along the bowel, moderate bloating;
• increase in body temperature within 38 ° C, short-term;
• intoxication is minor or absent;
• Dehydration is possible;
• meager respiratory syndrome;
• fast positive dynamics.
Laboratory diagnosis of rotavirus infection.
Specific research methods are aimed at detection of viruses in faeces with the help of RIF, ELISA, PCR
Rotavirus gastroenteritis is an anthropo-intestinal infection that affects mainly children( 90%) at the age of 6 months.up to 2 years. Diseases for weakened newborns are especially dangerous.
Human and animal rotaviruses belong to the genus Rotavirus of the family Reoviridae. The generic name comes from the Latin word Rota - the wheel, because on the electronic microphotography the shape of the outer capsid resembles the rim of the wheel, and the capsids of the inner capsid are wheel spokes. The virion genome is represented by a double-stranded( !!) RNA.
There are 4 serological variants( serovar) of human and animal rotaviruses, in addition to the common generic antigen, they have type-specific antigens corresponding to each variant in the outer capsid.
Rotaviruses with great difficulty are cultivated, for the stimulation of their reproduction using special techniques that increase the susceptibility of cells to viruses: add a trypsin solution to the cell culture, centrifuge. The output of mature virions from cells is accompanied by explosive cytolysis.
Rotaviruses are resistant to low pH( up to 3.0), conventional disinfectants, ether and detergents. For a long time( several months) they keep infectious activity in feces even at room temperature, in the cold - even longer. Sensitive to heating - boiling kills them instantly, in the presence of detergents they die already at 500 C.
Tropes to the epithelium of the villi of the small intestine. They multiply in the apical cells of villi, as a result of their death in the intestine the content of enzymes that disaggregate disaccharides - maltose, sucrose and lactose - is significantly reduced.
The intake of excess concentration of disaccharides in the large intestine with a chyme leads to a sharp increase in the volume of water: the absorption from the intestine is disturbed, in addition, water enters the lumen from the tissues due to an increase in the osmotic pressure. At the same time, inflammation develops rapidly in the mucosa. In sum, this leads to functional disorders with abundant diarrhea and a large loss of body fluids and salts.
From the destroyed villi viruses enter the lumen of the intestine and are excreted with feces into the external environment, where they can persist for a long time.
Transmission mechanism - fecal-oral, infecting children occurs most often through contact with the hands of adults, bed-clothes, other items. In 1 g of feces the patient contains up to 10 billion virus particles. Passive antiviral immunity due to antibodies of class Ig G - after 3 months.life is weakened, in the future it is supported only by antibodies of class IgA, contained in breast milk. Therefore, the infectious dose for young children can be small.
The source of rotavirus infection is a sick person with manifestations of diarrhea, which usually lasts about 1 week. The rise in morbidity is observed in the winter due to group outbreaks in children's institutions and maternity hospitals.
The incubation period averages 2 days( ranging from 12 hours to 3 days).Distinguish acute( in 20% of cases of infection), erased and asymptomatic clinical forms of infection. The classic symptomatology of acute viral gastroenteritis is characterized by a clinical triad:
• fever up to 38-39 ° C;
• vomiting;
• diarrhea with heavy loss of fluid.
Patients are concerned about abdominal pain, sometimes signs of inflammation from the side of the respiratory tract. With the rapid development of acidosis, a lethal outcome is possible.
Clinical symptomatology is observed up to 7 days, then the reconvalescence stage occurs, caused by the protective effect of factors of active humoral immunity - virus neutralizing antibodies of classes IgA and IgM.A feature of the course of rotavirus infection in 50% of young children is a longer( up to 3 weeks) isolation of the virus with feces after the disappearance of clinical signs of the disease. This fact has an important epidemiological significance if the child returns to the children's team after the illness.
Post-infectious immunity is quite strong and long, as it is supported by natural antigenic stimulation with periodic introduction of rotaviruses into the intestine from the outside.
Practical laboratory diagnostics is based on early detection of rotavirus antigens in coprofiltrates of feces, somewhat later - serum specific IgM class antibodies. In both cases, the enzyme-linked immunosorbent assay is most often used with appropriate test systems. For the indication of the virus in scientific epidemiological studies, the method of immunoelectron microscopy( IEM), tests of molecular hybridization, etc. are sometimes used.
Detection of rotaviruses in objects of the external environment presupposes a preliminary concentration of rotavir by adsorption chromatography on macroporous glass.
Treatment of involves pathogenetic therapy to restore the salt balance and acid-base balance in the patient's body. Apply oral or parenteral rehydration of the body with saline solutions.
Specific prophylaxis of is performed by antitroviral immunoglobulin for enteral administration. It is necessary to perform the usual methods of interrupting the transmission of the causative agent of intestinal infections from patients, based on strict observance of the rules of personal hygiene of staff and mothers in maternity homes, and the sanitary standards of childcare.